Best configuration for a Hobby CNC

Andrew

Thanks very much for clarifying what HSM means in the real world. Hafta admit that I sort of knew what it was but wasn't fully clear on the details of implementation.

The simple vector following system that I would have built just innately controls tooth load and cut velocity with a fixed step over and fix maximum depth of cut so much more basic. The analysis algorithm to verify the presets looks as if it could have been "interesting" but I never got that far.

Barrie

I know where you are coming from on the G-Code tweaking thing. A lot of my living depended on doing that sort of thing in my field.

But in my view a decently sophisticated system should be fire and forget not needing that sort of thing except for real edge cases. Mature G-Code on a mature controller should be sufficiently sophisticated for all normal use without editing. Lewis Hamilton makes his living by being uber good at tweaking his car to be just so for the track and getting the best out of it. I expect to just jump in my P38 Range Rover, fire up the V8 and go just about anywhere sane with no worries or extra effort.

Certainly the sort of market I was potentially aiming for had to be fire and forget.

I'd disagree that subtractive manufacturing has to remain a lot more specialised than 3D printing or laser cutting. In principle structure avoidance isn't an issue with true vector path systems. Basically every part of the machine has its own easily derivable path so the no go area where machine or cutter intersects a structure is computable. A trivial task for an analogue-digital hybrid, dunno about a pure digital computer but it oughtn't be that hard.

For materials and finishes you simply run an appropriate good quality cutter, whose loads are within the capability of the machine, as the maker advises. Complain if it doesn't do what it says on the tin.

Two steps down from a small Hass really! (The Hass Desktop training mill is, in mechanical layout at least, a main line machine makers version of the concept I had.) Not comparable to the big industrial boys in speed or capability but for a lot of work the job gets done without operator fiddling about or gotchas. Just slower and less than half the investment. A step or two up from a Tormach is the niche I guess.

Clive

I've had a couple of this chaps videos pop up as suggested ones on Youtube before, his latest one in interesting given the opening posts in this thread. He was using a Weiss mill converted to CNC and found it limiting when wanting to use HSM so has just finished converting it to an ATC spindle. Not only does he get the rapid tool change, a head that is half the weight which will speed up vertical rapids but where he was limited to 9" per min feed for a particular chip load he can now happily run at 72" per min due to the increase in spindle spoeed to 12,000rpm. Shows that HSM is available and wanting to be used in the home workshop.

Also like his idea of the "tramming blocks" that may be of interest to those with swivel head machines.

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That's a nicely made spindle and some pretty impressive traverse rates. I love the power drawbar. Really must get mine fitted. It's been on the sitting room floor for too long. My only disappointment is that what he's got is quick change tooling, not an ATC (automatic tool changer). That's a whole different ball game. I did look at the Tormach ATC, but it's expensive (~$5000) and offers no real advantage, to me at least. Of course in the professional world they're indisensable.

Andrew

From what I have seen once you have the spindle and the solenoid valves it is not that much more work to add a proper rack and program the machine to auto change, some of the spindles are available with tool holders ready to go to the next step. Though looking at the holders I can't see why you would not cut your own while once the basic machine is up and running as they don't look anything special. As you say unles sthere is one person looking after several machines it's not really needed if you are in the workshop on your own and can soon go over to the machine and change the tool.

He did seem to get more material being removed on the travel back to the start of the cut as the cuts got heavier which may be tool deflection or probably column flexing where it joins the base but as most of these clearing cuts are followed by a slower feed rate finish pass should not be a problem.

Only thing I did not like was him feeling the finished cut before the tool had stopped rotating!

Edited By JasonB on 30/08/2020 13:15:08

Distractions cause accidents. Absent-mindedly feeling a whirling job for sharp edges is typical, bet he doesn't do it normally.

Making a video whilst demonstrating a milling machine would completely trash my concentration. A visit from the cat unsettles me!

Dave

The saving grace that is was not your hand, nor mine.

Yes I thought that, after 50 years machining I have still got all my digits & eyes but mangled a few suds brushes in my time. I've now brought a powered mitre saw for DIY projects, another piece of kit to respect at all times!!!!

Tony